The present invention relates to an aircraft with a door arrangement for tightly closing a door opening.
Although applicable to any desired door arrangements, the present invention and the problem on which it is based are explained in more detail with reference to an aircraft passenger or freight door arrangement.
In order to load and unload an aircraft and in order for passengers and crew to get in and out, one or more openings are formed, usually in the aircraft fuselage, which openings can be closed by differently constructed door arrangements comprising doors and door frames. To close them, a respective door is positioned in a form-fitting manner within an associated door frame and locked mechanically. The door arrangements are to be able to be opened rapidly and simply but are to be tightly closed during the flight and should reliably absorb all of the loads which occur.
In particular in aircraft, which are equipped with a pressurized cabin, a door arrangement has to withstand the difference in pressure between an internal pressure, which is kept constant, within the pressurized cabin and a considerably lower external pressure at cruising altitude. For this purpose, seals are usually used between the door and door frame in order to prevent air from escaping from the pressurized cabin into the atmosphere through remaining gap openings between door and door frame.
FIG. 3 shows an example of a conventionel door arrangement of an aircraft with a seal of this type. Part of an aircraft fuselage skin 112 is illustrated in sectional view, in the vicinity of the edge of a fuselage opening with a door arrangement which comprises an aircraft door 106 and a door frame 104 connected fixedly to the skin 112. In the closed state shown, the door 106 is positioned in a form-fitting manner in the door frame 104 and is locked to the door frame 104 via a mechanical closing mechanism. For orientation purposes, the opening direction of the door 106 is marked by an arrow 206.
In the shown, closed state of the door arrangement, the outer surface 107 of the door 106 and the surface 109 of the skin are aligned with each other, they being spaced apart from each other via a gap 111. A sealing lip 300 is fastened to the inner surface of the door 106, said sealing lip being composed of a rubber-elastic material which, in the shown, closed state, is pressed against an opposite stop 302 of the door frame 104 by an application or locking force exerted by the mechanical locking. In the process, the rubber-elastic sealing lip 300 is deformed in order to match the shape of the stop 302. In order to show its elasticity, the sealing lip 300 is illustrated in a relaxed state, with its contours being overlapped in the illustration by the contours of the stop 302.
In the case of the conventionel door arrangement, an improvement in the sealing quality is desirable in order to completely withstand the pressure differences occurring during the flight, in particular at high flight altitudes, and to prevent air from the pressurized cabin of the aircraft from flowing past the seal into the outside atmosphere. However, a reinforcement of the mechanical locking in order to increase and uniformly distribute the application force, with which the sealing lip is pressed against a mating sealing surface such as the stop shown in FIG. 3, with the aim of improving the quality of the seal, would result in a substantial increase in the weight of the door arrangement.